/* 全局样式重置 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
    sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: #f5f5f5;
  color: #333;
  line-height: 1.6;
}

/* 主容器样式 */
.app-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 头部导航样式 */
.header {
  background-color: #409eff;
  color: white;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 导航菜单样式增强 */
.el-menu {
  background-color: #409eff !important;
  border: none !important;
}

.el-menu-item {
  color: white !important;
  transition: all 0.3s ease;
}

/* 鼠标悬停时文字保持黑色，背景呈现浅蓝色渐变效果 */
.el-menu-item:hover {
  color: black !important;
  background: linear-gradient(135deg, #66b1ff 0%, #99ceff 100%) !important;
}

/* 增强选中项效果，提高可见度 */
.el-menu-item.is-active {
  background-color: white !important;
  color: black !important;
  font-weight: 600;
  border-radius: 4px;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* 主内容区样式 */
.main-content {
  flex: 1;
  max-width: 1200px;
  width: 100%;
  margin: 20px auto;
  padding: 0 20px;
}

/* 页脚样式 */
.footer {
  background-color: #fff;
  padding: 20px 0;
  text-align: center;
  border-top: 1px solid #e6e6e6;
  margin-top: auto;
}

/* 卡片样式 */
.card {
  background: white;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  padding: 20px;
  margin-bottom: 20px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 5px 16px rgba(0, 0, 0, 0.15);
}

/* 按钮样式 */
.btn {
  display: inline-block;
  padding: 8px 16px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.3s ease;
  text-decoration: none;
  text-align: center;
}

.btn-primary {
  background-color: #409eff;
  color: white;
}

.btn-primary:hover {
  background-color: #66b1ff;
}

.btn-success {
  background-color: #67c23a;
  color: white;
}

.btn-success:hover {
  background-color: #85ce61;
}

.btn-warning {
  background-color: #e6a23c;
  color: white;
}

.btn-warning:hover {
  background-color: #ebb563;
}

.btn-danger {
  background-color: #f56c6c;
  color: white;
}

.btn-danger:hover {
  background-color: #f78989;
}

.btn-small {
  padding: 4px 8px;
  font-size: 12px;
}

.btn-large {
  padding: 12px 24px;
  font-size: 16px;
}

/* 表单样式 */
.form-group {
  margin-bottom: 16px;
}

.form-label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  color: #606266;
}

.form-control {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid #dcdfe6;
  border-radius: 4px;
  font-size: 14px;
  transition: border-color 0.3s ease;
}

.form-control:focus {
  outline: none;
  border-color: #409eff;
}

/* 课程卡片样式 */
.course-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.course-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.course-card-title {
  font-size: 18px;
  font-weight: 600;
  color: #303133;
  margin-bottom: 8px;
}

.course-card-info {
  font-size: 14px;
  color: #606266;
  margin-bottom: 8px;
}

.course-card-footer {
  margin-top: auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* 布局工具类 */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

.mt-10 {
  margin-top: 10px;
}

.mt-20 {
  margin-top: 20px;
}

.mb-10 {
  margin-bottom: 10px;
}

.mb-20 {
  margin-bottom: 20px;
}

.p-10 {
  padding: 10px;
}

.p-20 {
  padding: 20px;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .main-content {
    padding: 0 10px;
    margin: 10px auto;
  }
  
  .card {
    padding: 15px;
  }
  
  .course-card-title {
    font-size: 16px;
  }
}

@media (max-width: 480px) {
  .nav-container {
    padding: 0 10px;
  }
  
  .btn {
    padding: 6px 12px;
    font-size: 12px;
  }
  
  .form-control {
    padding: 6px 10px;
    font-size: 12px;
  }
}